Navigation Map In Areas Without Cellular Service

[dusty22]

Is navigation affected when driving through areas that have poor or no cellular coverage?

 

[kilpatds]

Yes.

• If you start navigating in an area with cell coverage, and never make any wrong turns, the only impact is loss of traffic-information (and sometimes maps won't draw in.) This is generally fine.
• If you start navigation in an area w/o cell coverage, it's a bit worse.
  • Small roads aren't known, and so the navigation system will just give up and not give you any route
  • Small roads aren't known, so if you get a route it might be disastrously stupid (uncommon)
  • No traffic-information, and frequently no drawn maps (because you were away from cell before it realized it needed that map tile)

And if you ever make a wrong turn, or stop for any reason while you're away from cell coverage, your previously "started w/ coverage" route will turn into a "started w/o coverage" one. This means that you stop for a bathroom break in the middle of BFE, and now your navigation functionally turns off (because it recalculates/starts again when you get back in, it can't find any road you're on, and so can't find a route and gives up)

Tesla could significantly improve this by just aggressively caching map tiles when you put in a route and start driving... just grab the tiles you'll need along route immediately. That wouldn't fix the "small roads" problem at all, except that you could then see the road path on the map and fake it. To fix the small roads problem, you'd presumably need to substantially increase the size of the navigation information it downloads.

 

[dusty22]

Thanks for your detailed explanation.

When you are not navagating to a destination, does the map continue to show the main roads and the car's location?

 

[E90alex]

Thanks for your detailed explanation.

When you are not navagating to a destination, does the map continue to show the main roads and the car's location?

If there is no service it will just show a blank grid once it runs out of cached map data.

 

[dusty22]

Thanks.

 

[stopcrazypp]

If there is no service it will just show a blank grid once it runs out of cached map data.

I think it's because the map drawing is provided by Google, while the navigation data is provided by a different vendor (which Tesla switched multiple times already, I remember TomTom and MapBox).

When completely offline, the navigation still can work using offline data, but it's back to the old fashioned one where you have to enter the exact address, with no autocomplete.

 

[dusty22]

I don't know much about these systems so excuse me for my basic qhestions

Where does GPS fit in with Tesla or does it at all?

 

[Tronguy]

I don't know much about these systems so excuse me for my basic qhestions

Where does GPS fit in with Tesla or does it at all?

Good basic question. GPS and NAV are joined at the hip. GPS, as you might expect, works pretty much everywhere except underground, like in tunnels. That locates the car on the map.

All Teslas (except ones that have aged out..) have basic 3G/4G telephone service which is used to draw the maps and put your location down. That part of it is just like a cell phone, a connected device from TomTom, or whatever.

Where things get weird: I used to use, back in the day, a non-connected GPS from TomTom that had a map from North America loaded into it. The GPS in the TomTom would find a bunch of satellites (neat graphics on that part, by the way), figure out the latitude, longitude, and altitude of where one was, and then place one on the map. Of course, this non-connected TomTom didn't know about traffic jams, bridges that were out, and so on.

Later, connected TomToms (and smart phones, and Teslas) didn't bother with keeping the maps for North America; they could get that data from over the air. That's part of Tesla's Standard Connectivity which is good, I think, for six years or so after buying the car. (Enhanced connectivity adds real-time traffic data: i.e., you can tell if there's a traffic jam ahead.)

There does appear to be some caching: Suppose that one is driving through the wilds of Nevada or something where there aren't any cell phone towers, but one set up the trip before entering the area with a dearth of 3G/4G. The car will have downloaded the maps before one enters the no-telephone area, so one still gets the maps until one comes out the other side. But, if one tries to start driving in such an area, the car's going to go looking for a 3G/4G connection - and isn't going to find one. So, blank screen, or just one with major highways but nothing else.

Android and iPhone smart phones have explicit ways around this: One can select an area in the map software in an area where one has 3G/4G/5G or even wi-fi, and tell the mapping software you want to save that area. There are likely limits to how big that area would be, but I've never explored said limits.

I note, however, that your sig says you live on Long Island. Um. You're surrounded by more cell phone towers than you can beat off with a stick where you live, so issues with caching and such, which mainly pop up in Extremely Uninhabited Areas (far West, northern Maine, etc.) are likely not to bother you in the least.

 

[dusty22]

Thanks for adding to my understanding of all of this.

Yes, we are well connected here, even have Tesla superchargers 2 miles from my home plus 4 or 5 others not much further away and 2 Tesla service centers 10 and 15 miles away.

But, I did find a dead zone nearby in the middke of all this connectivity; a half mile stretch of road in a well developed area. I would lose streaming and sometimes the map would start to go blank. I even took a test drive with a new M3 and it did the same thing as I drove down that road. Lately, I have had no more problems there; wondering if one of the recent updates had something to do with that. I remember something about improved connectivity was mentioned.

 

[Tronguy]

Thanks for adding to my understanding of all of this.

Yes, we are well connected here, even have Tesla superchargers 2 miles from my home plus 4 or 5 others not much further away and 2 Tesla service centers 10 and 15 miles away.

But, I did find a dead zone nearby in the middke of all this connectivity; a half mile stretch of road in a well developed area. I would lose streaming and sometimes the map would start to go blank. I even took a test drive with a new M3 and it did the same thing as I drove down that road. Lately, I have had no more problems there; wondering if one of the recent updates had something to do with that. I remember something about improved connectivity was mentioned.

Easy way to find out about the dead zone. As it happens, AT&T is the telephone provider for Teslas, at least in the US. Go to AT&T’s web site and look up ‘coverage map’.

Try and get the map and remove the 5G coverage, which Tesla’s cars don’t currently support, and you should see your dead zone.